Refrigerating apparatus



Oct. 31, 1944. A. A. MccoRMAc 2,361,854

REFRIGERATING APPARATUS Filed Dec. 27, 1940 2 Sheets-Sheet 1 Oct. 31, 1944. MOCORMACK REFRIGERATING APPARATUS Filed Dec. 27, 1940 2 Sheets-Sheet 2 IN VENTOR.

Patented Oct. 31, 1944 REFRIGERATING APPARATUS Alex A. McCormack, Dayton, Ohio, assignor to General Motors Corporation, Dayton, Ohio, a corporation of Delaware Application December 2'1, 1940, Serial No. 371,941

8 Claims.

This invention relates to refrigerating apparatus and more particularly to an improved arrangement for condensing the refrigerant.

An object of this invention is to increase the The motor-compressor-condenser unit It comprises a main frame 20 on which is mounted the motor 22 and the compressor 24. The compressor 24 is adapted to be driven by the motor 22 effective condensing surface without increasing by means of the shaft 26 Journalled directly in the the size of the condenser. main frame 20. The motor 22 is of conventional Another object of this invention is to utilize a construction and includes a stator 23 and a rotor filter element for increasing the effective con- 25. The stator 23 is supported on the cylindrical (lensing surface of a condenser. flange 36 formed integrally with the main frame One object of this invention is to materially in- 20. The compress 24 is a conventional t y crease the heat transfer surface of a condenser, compressor which has an inlet 2% and a comor the like, without the use of a plurality of heat D ess d refri erant outlet 30. radiating fins, A bell member 32 is secured to the frame 20 and Further objects and advantages of the present serves as a lubricant reservoir from which lubriinvention will be apparent from the following decant s upp t0 co s A econd scription, reference being had to the accompanybell member 3'3, also carried by the frame 2!), suring drawings, wherein a preferred form of the rounds the motor 22 and forms with the main present invention is clearly shown. frame a condensing chamber.

Inthe drawings: A water jacket 36 surrounds the motor frame Fig; 1 i a view partly in section showing my in. 36. Cooling water is supplied to the water jacket vention as applied. to a volatile refrigerant sys- 3% o h 11 inlet 49 a leaves e jac tam; through the outlet 52. The compressed refriger- Fig. 2 is a view partly in section showing 9. ant discharged through the compressor outlet 39 modified arrangement; and flows upwardly between the stator 3 and the Fig. 3 is an elevational view, with parts broken rotor 25 into th Show Surrounding he motor 22. away, of the condenser element shown in Fig. 2. When the compressed refrigerant strikes the out- One of the problems in designing a refrigerant er surface of the water jacket 38 it condenses and condenser is to provide a large enough surface in drains into the lowermost portion of the pocket thermal exchange with both the refrigerant t be formed between the casing 33 and the a e iackcondensed and the cooling medium. In a water 39 et 38. In order to increase the effectiveness of cooled condenser, for example, it is common practhe e posed area of the water jacket 38, i have tice to provide fins on the water coil but these secured a thin sheet of porous sintered monel or fins require considerable room and are expensive bronze material 4 to the outer surface of the to manufacture and assemble. I have found that Cooling W r jacket 38. This sintered material a more practical means for increasing the effecmay be brazed or otherwise secured to the outer tive condensing surface of a condenser witho t surface of the jacket 38. If desired, the sintered using the usual form of heat radiating fins is to mater l ay e u ed t u being nd i place a thin sheet of sintered metal in the con ny manner to the jacket It i d sira l densing chamber in contact with the water conhowever, to have direct physical contact between dult. 40 the outer surface of the water jacket 38 and the Referring now to Fig. 1, in which I have shown material 44. one system employing my invention, the reference By virtue of the large amount of exposed surnumeral I0 designates a sealed motor-compresface provided by the sintered material 44 the resor-condenscr unit of the type which is adapted frigerant gas will condense very rapidly. to withdraw refrigerant vapor from the evapora- 5 The ma erial 44 may be made in the followtor i2 and supply refrigerant in liquid form to the ing manner: A homogeneous mixture of finely evaporator l2. The flow of liquid refrigerant to divided nickel and copper powders is prepared, the evaporator i2 is controlled by means of a. conhaving about 68% nickel and 30% copper thereventional thermostatic expansion valve I6 located The degree of fineness of the metal p d r in the liquid line N. This valve is provided with 5 determines to a large extent the degree of porosthe usual form of thermostatic bulb I8 placed at ity of the final element. In constructing a pothe outlet of the evaporator and adapted to close rous sintered element such as 44 for use in a reoff the flow of refrigerant to the evaporator frigeratin-g system, it has been found that suitwhen the liquid refrigerant reaches the outlet of able porosity may be obtained when using powthe evaporator. ders which have been screened through a wire mesh screen having approximately 40 or even less openings per linear inch. The mixture of nickel and copper powders is spread loosely on the hard smooth surface of a graphite mold to form a loose mass. The top of the powder is scraped off to a smooth level surface by any suitable means to form a loose uncompacted layer of powder having the desired depth. The mold and uncompacted powder layer thereon is then heated in a non-oxidizing reducing atmosphere in a suitable furnace at a temperature of 2025' 1". for a short time, approximately eight minutes, to cause the nickel and copper particles to alloy or sinter together to form a highly porous metal sheet of an alloy having monel metal composition and which will resist corrosion to a high degree. After this sintering step is completed the porous metal sheet is cooled in a non-oxidizing or reducing atmosphere and then readily lifted from the hard graphite surface upon which it lay during sintering. This results in a hig ly porous sheet metal member which may be bent into the shape shown in Fig. 1.

While I have described specific metals in speciiic proportions, it is obvious that the proportions and the materials selected may be varied to form other alloys. In each case, the sintering temperature used being such as will cause the metal powders being used to alloy or sinter together without such melting as wil1 destroy the high porosity of the final metal structure. In order to provide a highly porous metal bronze member, for example, any desired proportions of copper and tin metal powders may be used in the process described hereinabove. For example, from 90% to about 97% copper powder may be used with from 10% to 3% of tin powder. The sintering temperature for the copper-tin mixtures is approximately 1500 F.

In Figs. 2 and 3 of the drawings, I have shown a modified refrigerating system embodying my invention. In this modified form a conventional rotary motor-compressor unit I is provided which withdraws vaporized refrigerant from the evaporator 52 and discharges compressed refrigerant through the outlet line 54 leading to a water cooled condenser element 58. The condenser element 56 comprises a pair of plate members 58 and 80 which are secured together by means of cap screws 62. A condensing chamber 64 is provided between the plate members ll and 60. Within this chamber there is mounted a porous sintered bronze or monel metal plate 8! to which is secured a spirally arranged water coil 68. Cooling water is introduced into the coil II at 10 and is discharged at 12. Referring to Fig. 2, it will be observed that the water pipes have been flattened so as to make it possible to arrange the spirals of the pipe close together and still leave room between adjacent spirals. The compressed refrigerant coming in contact with the water coil GI and the porous metal plate 88 will be condensed and will dmin into the lower portion of the chamber 84. The condensed refrigerant will leave the chamber 84 through the line H, which conveys the condensed refrigerant to the receiver 18. While I have shown a separate receiver for the condensed refrigerant, it is obvious that the condenser 86 may be made large enough to serve as a combined condenser and receiver. The flow of refrigerant from the receiver 16 to the evaporator I2 may be controlled by any conventional means such as the thermostatic expansion valve 18. In the arrangement as shown in Fig. 2, all of the refrigerant flowing through the condenser I0 is required to fiowthroughsomeportionortheotherofthe porous member OI. By virtue of this arrangement the member ll serves as a filter for the refrigerant.

The elements 44 and I may all be made by the same general process. The coil I may be secured to its-porous plate during the sintering process or may be secured thereto in a separate step by any conventional process of securing one metal member to another metal member. Preferably, however, the coil is secured to the porous plate during the sintering process. This may be done by placing the coil on top of the powder mixture before the sintering operation so that the coil is bonded to the material during the sintering process. If desired the coil may be imbedded in the material. The porosity and composition of the plates may be varied as explained hereinabove so as to suit the particular needs in each case.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. In combination, an evaporator, refrigerant liquefying means for supplying liquid refrigerant to said evaporator said refrigerant liquefying means comprising a motor-compressor unit, means for circulating a cooling medium in thermal exchange relationship with said unit, porous sintered metal means in contact with said last named means, and means for directing compressed refrigerant vapor in contact with said porous sintered metal so as to cool and condense said vapor prior to return to said evaporator.

2. In combination, an evaporator, refrigerant liquei'ying means for supplying liquid refrigerant to said evaporator, said refrigerant liquefying means comprising a motor-compressor unit, means for circulating a cooling medium in thermal exchange relationship with said unit, porous sintered metal means in contact with said last named means, and means for directing compressed refrigerant vapor in contact with said porous sintered metal so as to cool and condense said vapor prior to return to said evaporator, said porous sintered metal means comprising a jacket surrounding the motor portion of said motorcompressor unit.

3. In combination, an evaporator, refrigerant liquefying means fo supplying liquid refrigerant to said evaporator, said refrigerant liquefying means comprising a motor-compressor-condenser unit enclosed within a sealed casing, means for circulating a cooling medium in thermal exchange relationship with said unit, and porous sintered metal means in contact with said last named means, said refrigerant liquefying means including means for directing compressed refrigerant vapor in contact with said porous sintered metal so as to cool and condense said vapor prior to return to said evaporator.

4. In combination, an evaporator, refrigerant liquefying means for supplying liquid refrigerant to said evaporator, said refrigerant liquefying means comprising a motor-compressor-condenser unit, enclosed within a sealed casing, means for circulating a cooling medium in thermal exchange relationship with said unit, and porous sintered metal means in contact with said last named means, said refrigerant liquefying means including means for directing compressed refrigerant vapor in contact with said porous sintered metal so as to cool and condense said vapo prior to return to said evaporator, said porous sintered metal means comprising a jacket surround.- ing the motor portion of said motor-compressorcondenser unit. a

5. In combination, an evaporator, refrigerant liquefying means for supplying liquid refrigerant to said evaporator, said refrigerant liquefying means comprising a motor-compressor unit, means for circulating a cooling medium in'thermal exchange relationship with said unit, porous sintered metal means in contact with said last named means, means for directing compressed refrigerant vapor in contact with said porous sintered metal so as to cool and condense said vapor prior to return tosaid evaporator, said porous sintered metal means comprising a jacket surrounding the motor portion of said motorcompressor unit, and having a portion projecting into the condensed refrigerant.

6. In combination, an evaporator, refrigerant liquefying means for supplying liquid refrigerant to said evaporator, said refrigerant liquefying means comprising a motor-compressor unit, a

liquid refrigerant sump, and porous sintered metal means having one portion in said sump and having another portion arranged in thermal exchange with a portion 01 said motor-compressor unit.

7. A refrigerating system comprising in combination, an evaporator, a compressor and a condenser connected in refrigerant flow relationship, said condenser comprising a porous sintered metal plate member through which substantially all of the refrigerant flowing through said condenser is required to pass, and means for flow ing a cooling medium in thermal exchange with said member and the refrigerant flowing through said member.

- 8. A refrigeratingsystem comprising in combination, an evaporator, a compressor and a condenser connected in refrigerant flow relationship, said condenser comprising means forming a condenser cooling fluid passage and a prefabricated sheet of porous sinter'ed metal arranged in physical contact with said means and serving to present a large continuous condensing surface to the compressed refrigerant gas in said condenser.

' ALEX A. MCCORMACK. 

